Method of the preparation of macroporous foam comprising zeolite or zeotype material

ABSTRACT

The present invention provides a macroporous foam comprising microporous zeolite or zeotype material and preparation thereof, which comprises dipping a polymeric template capable of releasing an amine which has a sponge or macroporous structure and can be selected from a group consisting of polyurethane, polyamides, aromatic or aliphatic polyimides, polyamideimides, epoxy resins having an amine skeleton, and polymeric materials capable of releasing an organic amine by hydrolysis, in an alkaline or acidic solution, gel or sol of a precursor of said zeolite or zeotype material, and reacting the resultant at a suitable temperature for a period such that all or almost all of the polymeric template can be replaced with zeolite or zeotype material. Said foam comprising zeolite or zeotype material has the outer shape and size and the inner sponge or macroporous structure which are the same or similar to those of the polymeric template used.

TECHNICAL FIELD

The present invention relates to macroporous foams comprisingmicroporous zeolite or zeotype material, and to a method for thepreparation thereof by using polymeric templates having a thread or filmform or a sponge structure. More particularly, the present inventionrelates to macroporous foams which are prepared by using polymerictemplates having a thread or film form or a sponge structure tocrystallize microporous zeolite or zeotype material in a thread or filmform or a sponge structure, and to a method for the preparation thereof.

BACKGROUND ART

The present invention belongs to the inorganic synthesis of synthesizingmolecular sieves including zeolite or zeotype materials. “Zeolite” is ageneric name of crystalline aluminosilicate, which constitutes the poreskeleton of zeolite molecules and bears an anionic charge for eachaluminum atom. Cations for offsetting such anion charges are presentwithin the very fine pore space which is regularly formed and has a sizeof not more than 2 nm and the remaining pore space is filled with water.The 3-dimensional pore structure of the zeolite molecules variesdepending on the shape and size of the pore, and the pore diameter isusually corresponding to the size of molecules. Therefore, based on theshape and size of the pore, zeolite has the size selectivity for amolecule entering into the pore, and thus, zeolite is called as amolecular sieve.

In the context of the present invention, since zeolite and zeotypematerials have micropores having a size of from a few nanometers toseveral tens nanometers, they are considered as being “microporous”.

Microporous zeolite and zeotype materials are widely used in the fieldof households and various industries as a catalyst, adsorbent, ionexchanger, water-absorbing agent, etc. For examples, zeolite showsdiverse chemical and physical properties depending on its chemicalcomposition, structure, pre-treatment method, etc. Especially, zeoliteitself has a resistance to high temperature and a modified zeolite inwhich protons are replaced with other cations represents a strong acidicproperties to serve as a strong solid acid, the modified zeolite iswidely used as a cracking catalyst of crude oil in the petrochemicalindustry. In addition, such acidic zeolite is widely used as acidcatalyst in various chemical reactions as well as a ion exchanger,water-absorbing agent, adsorbent, gas-purifying agent, carrier for apurifying catalyst of exhausting gases of internal combustion engines,additives for detergent, soil improving agent, additives for animalfeed, etc. Further, an extensive study is now being made on itsapplication as a sensor carrier in which zeolite is shaped in the formof a thin membrane.

Meanwhile, there are many known zeotype molecular sieves wherein a partor all of silicon (Si) and/or aluminum (Al) atoms constituting thestructural skeleton of zeolite molecule are replaced with otherelements. For example, a porous silicalite-type molecular sieve in whichaluminum atoms are completely eliminated, an alpo(AlPO₄)-type molecularsieve in which silicon atoms are replaced with phosphorous atoms, andother molecular sieve or zeotype material wherein skeleton metal atomsare partially replaced with various metal atom such as Ti, Mn, Co, Fe,Zn, etc., have been developed and widely used. In recent, many studiesare also being made on mesoporous materials (MCM-series silica) of whichpore size is up to several tens nanometers.

Such molecular sieves such as zeolite or zeotype materials are preparedby crystallizing the precursor thereof and generally obtained in theform of fine powder with a diameter of less than about 10 micrometers.

When such zeolite or zeotype materials in the form of powder are filledin a container or reactor, it difficult for a liquid or gaseous fluid toflow through the powder since the spaces between the powder particlesare too small. Therefore, a very high pressure is required in order tomaintain a sufficient flow velocity in the container or reactor filledwith molecular sieve powder, which causes problems that much energy isconsumed and the cost for the production of the equipment and reactor isincreased. There has been proposed various countermeasures in order toavoid such process problems owing to the pressure dropping phenomena.

A most commonly known method is the method of preparing a zeolite-claycomposite, wherein zeolite powder is conglomerated by using clay as abinder to form a paste, which is then granulated to granules with a sizeof several millimeters, or is extruded in the form of noodle and thencut in a short length [Breck, D. W. Zeolite Molecular Sieves 725-755(John Wiley & Sons, New York, 1974)]. However, the above-describedmethod requires a mixing step of mixing zeolite with clay, a shapingstep, and subsequent treating steps, which causes problems that theoverall procedures are troublesome and overall cost for the productionis increased. Further, since clay itself is considered as an impurity,the purity of zeolite in the composite is decreased, which causes adecrease of the zeolite using efficiency. Since pores may be blocked byclay particles, the zeolite using efficiency will be rapidly decreased.

In addition, as to granules or extrudates having a size of more thanseveral micrometers, only the zeolite molecules present in the surfaceof a granule or extrudate generally participate in a reaction sincereactants cannot easily access or penetrate into the inner portion ofthe granules or extrudates. Therefore, if zeolite is conglomerated bymixing with clay, the zeolite using efficiency will be greatlydecreased. In addition, as to granules having a size of more thanseveral micrometers, uniform reactivity at a uniform reactiontemperature cannot be obtained since there is a temperature differencebetween the surface and the inner portion of a granule when a reactionis proceeded.

Another widely known technology is the method of coating zeolite film ona support having macropores of millimeters size, wherein the support ismade of aluminum, alumina, stainless steel or the like in the form ofhoneybee or the like in order to facilitate the spread of molecules andvarious zeolite is coated thereon in the form of a thin film [Bein, T.Chem. Mater. 1996, 8, 1636-1653; Caro, J., Noack, M., Klsch, P. &Schfer, R. Microporous and Mesoporous Materials 2000, 38, 3-24; Clet,G., Jansen, J. C. & van Bekkum, H. Chem. Mater. 1999, 11, 1696-1702;Boudreau, L. C., Kuck, J. A. & Tsapatsis, M. J. Membr. Sci. 1999, 152,41-59; van der Puil, N., Dautzenberg, F. M., van Bekkum, H. & Jansen, J.C. Microporous and Mesoporous Materials 1999, 27, 95-106; Kormarneni,S., Katsuki, H. & Furuta, S. J. Mater. Chem. 1998, 8, 2327-2329].

The zeolite-support composite particles thus prepared have advantagesthat the spread of reactants and products and the thermal transfer inall directions are easy, and the temperature distribution is uniform,etc., whereas the efficiency of zeolite used per unit weight are verysmall since the amount of zeolite used is much less than that of thesupport. In addition, since the thermal expansion coefficient of thezeolite is different from that of the support, repeated heating of saidcomposite during the process may cause the deprival of the zeoliteparticles from the support. Further, since the amount of zeolite coatedon the support is much less than that of the zeolite precipitated on thebottom of the reaction vessel during the coating process, there issevere waste of zeolite synthetic gel.

Sterte et al. describe a technology to form macropores in a zeolite masswherein spherical ion exchange resin and active carbon are used as asupport and said support is dipped in a synthetic gel to form zeolitethereon by a secondary crystal growing method and then removed byburning [Tosheva, L., Valtchev, V. & Sterte, J. Microporous andMesoporous Materials 2000, 35-36, 621-629; Valtchev, V., Schoeman, B.J., Hedlund, J. Mintova, S. & Sterte, J. Zeolites 1996,17, 408-415].However, since the ion exchange resin used as support is more expensivethan zeolite and the zeolite mass has only a size of several hundredsmicrometer, there is still caused a pressure depression phenomenon in areal application.

Anderson et al. report a direct converting method of porous diatomaceousearth diatom to zeolite by hydrothermal method [Anderson, M. W., Holmes,S. M., Hanif, N., & Cundy, C. S. Angew. Chem. Int. Ed. 2000, 39,2707-2710]. In such case, there is an advantage that molecules caneasily enter and leave via the macropores that the diatomaceous earthpossesses by nature. However, since the particle size of thediatomaceous earth itself is basically small, for example of severaltens μm, a second shaping step using a binding agent such as clay, etc.should also be needed in order to utilize them.

Stein et al. report a technology wherein polystyrene beads having auniform size of about 100 micron are compactly charged, amorphous silicais charged and formed in the void space of said beads, and then saidamorphous silica is converted to silicalite-1 which is one of zeotypematerials, by a secondary method [Holland, B. T., Abrams, L. & Stein, A.J. Am. Chem. Soc. 1999, 121, 4308-4309]. This technology can afford asilicalite-1 in which macropores are distributed, but the overallprocess is complicated and has a limitation that it cannot be appliedfor the preparation of zeolite mass comprising both of aluminum atom andsilicon atom. Further, a practical use of this technology is difficultin view of economics since the polystyrene beads used are expensive.

Under such circumstances described above, technical problems to besolved in the present invention are as follows:

1) In the foam mass formed with zeolite or zeotype materials, macroporesthrough which molecules can freely spread should be spatiallycommunicated with each other and uniformly distributed all over the foammass.

(2) The size and shape of macropores formed in a foam should be adjustedin a free and unrestricted manner.

(3) The 3-dimensional outer size and outer shape of a foam comprisingzeolite or zeotype materials should be adjusted in a free andunrestricted manner.

(4) The thickness and shape of the layer comprising microporous zeoliteor zeotype materials which surrounds the macropores should be easilyadjusted, and therefore, the mechanical strength of the foam should becontrolled.

(5) Template should be inexpensive, diverse, and easily available.

(6) Preparation processes should be simple.

(7) Processing time should not be long.

(8) There should be reproducibility.

(9) Zeolite and zeotype materials of the foam thus prepared should havea high purity.

(10) Mass production should be allowed.

The present inventors have found that, if a solution, sol or gel of aprecursor of zeolite or zeotype materials are charged in a polymerictemplate having a sponge structure and aged under alkali or acidiccondition to crystallize the zeolite or zeotype materials, it ispossible to obtain a foam comprising zeolite or zeotype materials andhaving a sponge structure which is nearly completely resembled to thatof the template used, with solving most of or all of said technicalproblems to be solved as described above.

By using the method proposed in the present invention, it is possible toprepare a foam comprising zeolite or zeotype materials in whichmacropores (pores having a size of 100 nanometers) are organicallylinked with each other and have a size of several hundreds micrometers,and therefore, the pressure depressing phenomenon disappears sincemolecules can move through the macropores present in the foam.

In addition, since it is possible to freely shape template and thus forma zeolite foam having a desired outer shape, a separate shaping step inwhich clay is used to shape zeolite in a specific form is not needed andthus the cost for the production is remarkably decreased. Further, sincethere is no blocking problem owing to a binding agent, molecules canfreely move inside the zeolite foam having various outer shapes and thusthe zeolite using efficiency is substantially increased to nearly 100%.

In addition, since zeolite is formed in the form of a thin layer in thefoam even without any separate support, the zeolite using efficiency isfurther improved. And since molecules can freely enter and leave thenanopores via the macropores, the thermal transfer into the inside ofthe foam is easy and a uniform reactivity owing to a uniform temperaturedistribution may be expected.

According to the present invention, therefore, both of the problems ofthe prior art caused by too small size of synthetic zeolite particlesand the problems encountered in the macroporous granule or extrudatewhich is proposed to solve the problems of the prior art caused by toosmall size of synthetic zeolite particles can be solved and the objectto maximize the zeolite using efficiency can be achieved.

DISCLOSURE OF INVENTION

The first object of the present invention is to provide a foam which isprepared by using a polymeric template capable of releasing an amine tocrystallize zeolite or zeotype materials in the inner structure andouter shape the same with or similar to those of said template.

According to the concept and theory, it is possible to prepare anarticle comprising zeolite or zeotype material that is fitted to theinner and outer structure of a polymeric template capable of releasingan amine. Therefore, a variant wherein a polymeric template having afilm form is used to prepare an article of film form does not deviatethe scope of the present invention.

Therefore, according to one preferred embodiment of the presentinvention, a polymeric template capable of releasing an amine has asponge or macroporous structure. In such case, thus prepared foamscomprising zeolite or zeotype material has a sponge structure the samewith or similar to that of said template.

According to another preferred embodiment of the present invention, apolymeric template capable of releasing an amine has a form of3-dimension, film, thread or woven fabrics.

In the context of the present invention, the term “sponge structure” canbe understood to illustrate the macroporosity of the polymerictemplates. If a part or all of the macropores or bigger inner spacesthan said macropores are spatially communicated with each other, it canbe expressed as having a sponge structure.

The second object of the present invention is to provide a method forthe preparation of a foam, wherein a polymeric template capable ofreleasing an amine is used to crystallize zeolite or zeotype materialsin the inner structure and outer shape which are the same with orsimilar to those of said template.

As described above, a polymeric template capable of releasing an aminehas a sponge or macroporous structure, and has a form of 3-dimensionalmass, film, thread or woven fabric.

According to one preferred embodiment of the method of the preparationof the present invention, it comprises dipping a polymeric templatecapable of releasing an amine group in an alkaline or acidic condition,into a sol or gel containing a precursor of a zeolite or zeotypematerial, and aging the resultant at a suitable temperature for a periodsuch that the polymeric template can be completely or nearly completelyreplaced with the zeolite or zeotype materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be illustrated by reference with the drawingsattached.

FIG. 1 shows a photo of a ZSM-5 foam according to the present invention,which is prepared by using a cylindrical polyurethane sponge (size of Φ13 cm×27 cm) as a template. Said huge ZSM-5 foam having a diameter of 13cm and a height of 27 cm shows that it is possible to prepare a foamhaving any huge size.

FIG. 2 shows a photo wherein polyurethane sponge templates havingvarious shapes and corresponding ZSM-5 foams having the same shape arearranged in pairs. It can be shown that it is possible to prepare atemplate having various shapes when it is needed, as well as the foamthus prepared has a outer shape that is little changed from that of theoriginal polyurethane sponge template.

FIG. 3 shows SEM photos (a and c) of the inner structure of polyurethanesponge and SEM photos (b and d) of the inner structure of ZSM-5 foamsprepared by using them as a template. The length of the bar at theright-bottom corner is 500 μm, which is the same in the drawings below.

As can be seen in FIG. 3, since macropores of 300˜800 μm surrounded by athin ZSM-5 film is communicated with each other via windows of 100˜300μm, molecules can freely enter and leave said macropores as well as finenanopores in said ZSM-5 film surrounding the macropores and therefore,can contact with an acid site and/or active site in said nanopores toproceed a chemical reaction such as catalytic reaction, adsorption, ionexchange, etc. Therefore, zolite foam as described above in whichmacropores are spatially communicated with each other and uniformlydistributed can be an ideal zeolite mass.

FIG. 4 shows SEM photos of ZSM-5 foams prepared by using as templatespolyurethane sponges having different inner structures from each other.As such, the present invention has a feature that it can perfectlyreproduce the outer shape as well as the inner structure of thepolymeric material used as a template

FIG. 5 shows SEM photos of the cross sections of zeolite films preparedin various thickness and shapes at a temperature of 100, 120, 140 and180° C., respectively. It can be shown that it is possible to freelyadjust the thickness and the surface shape according to the reactiontemperature.

FIGS. 6, 7 and 8 shows X-ray diffraction (XRD) patterns of powders offoams comprising zeolite or zeotype materials which are prepared byusing polyurethane sponges as a template according to the presentinvention, wherein said pattern are determined by using powder of aZSM-5 foam (FIG. 6), a Zeolite-A foam (FIG. 7) and a Zeolite-Y foam(FIG. 8). It can be understood from said patterns that the crystalstructure of the desired molecular sieve is very purely obtained evenwhen a polymeric template of the present invention is used.

The present invention is illustrated below more specifically.

In the context of the present invention, the term “nanopore” meansmicropores having a pore size of from several nanometers to several tennanometers which are present in zeolite or zeotype materials. The term“macropore” means large pores having a pore size of from several tenmicrometers to several hundred micrometers, which are surrounded by thinlayer or film of zeolite or zeotype materials. In the context of thepresent invention, the term “microporosity” means that there are suchnanopores and the term “macroporosity” means that there are suchmacropores.

In the present invention, the term “template” means that it serves as atemplate when zeolite or zeotype material is generated. If the synthesisof zeolite or zeotype material is completed, the template materialcompletely or almost completely will disappear and the spaces occupiedby the template material and the adjacent area thereof will be occupiedby zeolite or zeotype material.

In the present invention, by using a template having a film or a spongestructure, the outer shape of the template as well as the inner spongestructure and macropores thereof are perfectly reproduced. Therefore,when the template used has a film form, the resulted foam will has afilm form, and when the template used has a macroporous or spongestructure, the resulted foam comprising zeolite or zeotype material willbe formed so as to be macroporous or to have a sponge structure.

The polymeric materials which can be used as a polymeric template in thepresent invention are polymeric materials capable of releasing anorganic amine or ammonium under an alkaline or acidic conditions,preferably has a sponge-like structure in which the inside macroporesare spatially linked to each other. A polymeric template having a filmform may be employed when a thin zeolite film or layer is needed. Insuch case, the template may not have a sponge structure.

Polymeric materials that can be employed as a template include naturalor synthetic polymers or condensates, and for example, they can beselected from a group consisting of:

(1) polymers of polyurethane types, for example, prepared by using apolyol or polyhydric alcohol having two or more alcohol groups and anisocyanate,

(2) polymers of polyamide types, such as nylons, peptides, silk, etc.

(3) aromatic or aliphatic polyimides, for examples, prepared bycondensing a dianhydride and a diamine, etc.,

(4) polymers of polyamideimide types,

(5) polymers of epoxy resin types, in which amine or its derivatives,such as urea, melamine, guanamine, etc. constitute the skeleton of thepolymer,

(6) other polymers which can be hydrolyzed by an acid or base to releaseorganic amino groups.

The shape of template used in the present invention is not specificallyrestricted and generally has the following shapes:

(1) 3-dimensional mass or 2-dimensional film,

(2) thread or woven fabrics.

When said type of the polymeric templates as listed above are employed,the principle that zeolite or zeotype material is generated in the sameshape of the template is explained by using an example of a polyurethanetemplate of a film shape as follows:

A polyurethane film itself without any support is dipped in a gel forsynthesizing molecular sieve, or a polyurethane film is attached on asupport such as glass, quartz, silicon wafer, porous alumina, porousstainless steel, etc. and then dipped in a gel for synthesizingmolecular sieve to proceed a reaction.

The polyurethane is hydrolyzed under a basic condition to generate analcohol (R¹—OH) and an organic amine (R²—NH₂).

In general, since a precursor of zeolite or zeotype material can easilyform the crystal of zeolite or zeotype material, said organic aminegenerated from polyurethane as described above can serve as a “frame”for the synthesis (crystallization) of zeolite or zeotype material

That is, polyurethane template is decomposed under acidic or basiccondition to generate organic amines, and thus resulted organic aminesserve as a frame and zeolite or zeotype material is formed from theprecursor thereof and then crystallized. At this time, the polyurethanetemplate will be uniformly decomposed, the concentration of the organicamine frames is maintained constantly, and simultaneously, the zeoliteor zeotype material will surround said organic amine frames uniformly.As a result, a zeolite film having a uniform thickness will be formedalong the surface of the polyurethane film template.

The above process will be continuously lasted until all the polyurethanetemplate material is exhausted, if the decomposition of polyurethane islasted and the synthetic solution, gel or sol remains. Therefore, if thethickness of polyurethane film is increased and the synthetic solution,gel or sol is used in a sufficiently excess amount, a thick film ofzeolite or zeotype material can be obtained.

In addition, if synthetic gel remains sufficiently and the reaction timeis sufficiently prolonged even after all the polyurethane templatematerial is exhausted, zeolite or zeotype material formed serves as aseed for the crystal growth and then zeolite crystals of variousorientation will continuously grow. Thereby, it is possible to make afilm thicker, and as a result, it is possible to adjust the thickness ofa film. Further, by controlling the conditions of crystallization, it ispossible to orient the surface crystals, for example, to cover thesurface of the film comprising zeolite or zeotype material with sharpcrystals.

When a polymeric template having a sponge structure is used, the abovezeolite or zeotype material can be prepared so as to reproduce the abovesponge structure and the reaction can be proceeded until zeolite orzeotype material completely replaces the polymeric template. In suchcase, it is possible to adjust the inner structure of the spongestructure, that is the thickness of the wall and the size of poresaccording to the conditions such as the type of materials used, reactiontemperature, etc. In here, a person of ordinary skill in the art candetermine the conditions to be necessary by a simple experiment andexamination.

In general, zeolite or zeotype material is synthesized and crystallizedunder a basic condition, and a mesoporous silica such as MCM, SBA, MSU,KIT is synthesized and crystallized under an acidic or a basiccondition. For reference, as to the types (e.g., MCM, SBA, MSU, KIT) andphysical properties thereof of mesoporous silica, and the synthesis andcrystallization method thereof, it is possible to refer to prior art,all of which is included in the present invention for reference.

With the same principle as described above, all polymer which can behydrolyzed under a basic condition to release an organic amine can beused as a template for the preparation of foams comprising zeolite orzeotype material, and similarly, all polymer which can be hydrolyzedunder an acid condition to release an organic amine can be used as atemplate for the preparation of foams comprising mesoporous silica.

Therefore, an organic amine in the term “polymer capable of releasing anorganic amine” includes compounds having an ammonium group.

In the present invention, the organic amine generated by a hydrolysiscan serve as a frame for the synthesis of zeolite or zeotype material,as well as a promoter to accelerate the synthesis/crystallization.

The precursors for the synthesis of zeolite or zeotype material, themethods and conditions therefor are well known in the art, for example,the precursors, the synthetic methods and conditions described in theabove prior art can be mentioned. These are incorporated in thespecification of the present invention for reference.

Thus prepared foams comprising of zeolite or zeotype material of thepresent invention can be employed in all the fields to which aconventional zeolite or zeotype material can be applied, but also theyrepresent good effects as follows:

(1) Easy and Free Adjustment of the Shape and Size of Foams

Since a template is made of polymeric materials so as to have a desiredsize and shape and a zeolite foam thus prepared therefrom reproduces theshape and size of the template used, zeolite foams of the presentinvention can be obtained in a size and shape that are substantiallydesired by a user.

On comparing with prior technology using a binding agent such as clay,the present invention does not need any mixing step with a binding agentand any shaping step, and therefore, the production cost can be greatlylowered.

In addition, the easiness of the adjustment of the 3-dimensional shapeand size of foams can make it possible to appropriately design a foamand then to easily fit it to a reaction vessel's shape. Therefore, thereis no troublesome step such as steps of filling and removing zeoliteparticles in the vessel.

The easiness and freedom of the adjustment of the size and shape offoams are illustrated in FIGS. 1 and 2 attached.

(2) Spatially Communicated Macropores of a Foam

Since macropores in a foam (macropore size of several hundreds μm toseveral thousands μm) are spatially communicated with each other and thedistribution density and pore size thereof are uniform all over thefoam, it is possible for molecules such as reactants, products, catalystand/or solvent to freely move and/or spread via such macropores. As aresult, there is no pressure-depressing phenomenon in any way.

The shape of spatially communicated macropores is well illustrated inFIGS. 3 and 4 attached.

(3) Purchase Easiness of Template Materials and their Low Price

Polymeric materials such as polyurethane used as templates are easilyavailable and inexpensive. Further, it is another advantage thatcharacteristics of pores can be adjustable.

(4) Possibility to Adjust the Macroporous Characteristics

Since template materials having very various kinds and characteristics(e.g., porosity and mean pore size) are easily available, it is possibleto prepare a foam comprising zeolite or zeotype materials which hasvarious usefulness and macroporous characteristics.

(5) No Problem on the Occlusion of Macropores

Since a zeolite foam prepared according to the present invention doesnot use any binding agent, there is no or little occlusion of macroporesand thus it is possible for molecules to freely move to any place in thefoam via the macropores. Therefore, the efficiency of using zeolite orzeotype materials can increase to nearly 100%.

(6) Thin Inner Wall of the Macropores

Since the zeolite or zeotype material is present in the form of thinfilm, it is possible for molecules to freely enter and leave the zeolitenanopores. As a result, the spread of molecules into the nanopores ofzeolite and the macropores of a foam does not decrease the overallreaction rate.

(7) Possibility to Adjust the Thickness of Inner Wall of Macropores

The thin film of zeolite or zeotype material which constitutes the innerwall of the macropores in a foam can be adjusted by changing the amountof reactants, reaction temperature and time or the like, and thus, it ispossible to adjust the thickness of inner wall of macropores. Therefore,the molecule diffusion velocity and mechanical strength of a foam can beadjusted.

An adjustment of the film thickness of a foam depending on the reactiontemperature is illustrated in FIG. 5 attached.

(8) Economy of the Foam Production

The present invention is suitable to a mass production of foams in a lowprice, owing to a simple procedure of the foam production, a shortprocess time, a high foam purity, a high reproducibility, a low price oftemplate materials, and an easiness of availability of the templatematerials in large quantity.

(9) Novel Use

Foams comprising zeolite or zeotype material prepared according to thepresent invention can be employed in all the fields to which powder ofzeolite or zeotype material is conventionally applied, such as, forexample, catalyst, catalyst carrier, adsorbent, ion exchanger, absorbingagent, etc., as well as in the fields to which powder of zeolite orzeotype material cannot be applied till now, such as, for example, apurifying catalyst of exhausting gases of automobiles or a catalystcarrier.

As stated above, the present invention can solve the problems caused bythe reason that the particles of conventional synthetic zeolite orzeotype material are too fine, and thus can contribute the maximizationof zeolite using efficiency.

EXAMPLES

The present invention is further illustrated by referencing the Examplesin below, which by no means restrict the present invention.

Example 1 Preparation of a Silicalite-1 Foam Using a Polyurethan Spongeas a Template

A 1M solution of tetrapropylammoniumhydroxide (TPAOH), which is used asa template for the preparation of zeolite or zeotype material such aszeotype material having a structure of MFI configuration, is added to100 g of distilled water, to which 25 g of tetraethyl orthosilicate(TEOS) is added as silicone source and completely hydrolyzed understirring.

In 30 g of the resulted colorless and transparent gel for thepreparation of silicalite-1, 0.4 g of a polyurethane sponge having asuitable size is dipped to be soaked with the gel. The resulted spongeis then subjected to a synthetic reaction in an autoclave at 80˜250° C.for 2 days. After the reaction, the resulted silicalite-1 foam is washedwith distilled water and acetone. The weight of foam thus finallyobtained is about 2 g.

Example 2 Preparation of a ZSM-5 Zeolite Foam Using a PolyurethaneSponge as a Template

The same procedure as described in Example 1 is repeated to prepare afoam product, except that 0.65 g of sodium aluminate (NaAlO₂) asaluminum source is further added to the gel for the preparation ofsilicalite-1 in order to synthesize ZSM-5 zeolite.

The ratio of silicon to aluminum in the synthetic gel thus prepared isabout 25:1.

Example 3 Preparation of a TS-1 Foam Using a Polyurethane Sponge as aTemplate

The same procedure as described in Example 1 is repeated to prepare afoam product, except that 0.67 g of titanium tetraisopropoxide astitanium source and 10 ml of isopropanol are further added to the gelfor the synthesis of silicalite-1 in order to synthesize TS-1 typemolecular sieve.

The ratio of silicon to titanium in the synthetic gel thus prepared isabout 50:1.

Example 4 Preparation of a Metallo-silicate-1 Foam Using a PolyurethaneSponge as a Template

The same procedure as described in Example 1 is repeated to prepare ametallo-silicate-1 foam, except that a solution in which a salt of atransition metal (Fe, V, Co, Mn, Cr, Cu, etc.) is dissolved in distilledwater is further added to the gel for the synthesis of silicalite-1. Thetransition metal salt used is FeCl₂, VOCl₃, CoCl₂, MnCl₂, CrCl₃ orCuCl₂, respectively.

The amount of the transition metal salts used is adjusted such that theratio of silicon to transition metal in the synthetic gel thus preparedis about 100:1.

Example 5 Preparation of a MEL-type Zeolite (Silicalite-2, ZSM-11, TS-2,Metallo-silicalite-2) Foam Using a Polyurethane Sponge as a Template

43.8 g of a 20 wt % aqueous solution of tetrabutylammonium hydroxide(TBAOH), which is used as a template for the preparation of zeolite orzeotype material having a structure of MEL configuration, is added to 41g of distilled water, to which 10 g of TEOS is added as silicone sourceand completely hydrolyzed under stirring.

To the resulted colorless and transparent synthetic gel, is addedNaAlO₂, titanium tetraisopropoxide, FeCl₂, VOCl₃, CoCl₂, MnCl₂, CrCl₃and CuCl₂ as the source of aluminum, titanium or a transition metal (Fe,V, Co, Mn, Cr, Cu, etc.), respectively, after mixing them with 10 g ofdistilled water in an amount to satisfy the following composition ratio:

x MO_(y): 0.88 TBA₂O: z Na₂O: 1 SiO₂: 99 H₂O

wherein, M represent an element such as Al, Ti, Fe, V, Co, Mn, Cr or Cu,x and z are independently a value between 0˜0.1.

The subsequent procedure is similar to that of Example 1 and carried outat 50-250° C. depending on the constitutions and their ratio.

Example 6 Preparation of a Beta-zeolite Foam Using a Polyurethane Spongeas a Template

32.4 g of a 35 wt % solution of tetraethylammonium hydroxide (TEAOH),which is used as a template for the preparation of beta zeolite, ismixed with 1.3 g of distilled water, to which 0.65 g of NaAlO₂ asaluminum source and 10 g of TEOS as silicone source are added andcompletely hydrolyzed under stirring.

The composition of gel thus obtained is as follows:

2 Al₂O₃: 31.4 TEA₂O: 3 Na₂O: 100 SiO₂: 1020 H₂O.

The subsequent procedure of producing a beta zeolite foam is similar tothat of Example 1 and carried out at 50˜250° C.

Example 7 Preparation of a Zeolite-A Foam Using a Polyurethane Sponge asa Template

Zeolite-A containing tetramethylammonium hydroxide (TMAOH) ion issynthesized as follows:

Firstly, 27 g of TMAOH (25 wt %) is mixed with 100 g of water, to which5.7 g of aluminum isopropoxide is added and the hydrolysis is carriedout under stirring. To the resulting transparent gel, a solution of 0.57g of NaCl in 10 g of distilled water was added. Finally, 9 g of silicasol (SiO₂ 40 wt %) as silicon source is added and well mixed.

The composition of the gel thus obtained is as follows:

0.35 Al₂O₃: 0.92 TMA₂O: 0.25 Na₂O: 1.5 SiO₂: 150 H₂O.

The subsequent procedure of producing a zeolite foam is similar to thatof Example 1 and carried out at 50˜250° C.

Example 8 Preparation of a Zeolite-Y Foam Using a Polyurethane Sponge asa Template

TMAOH is used as a template as in the preparation of zeolite-A ofExample 7. 29.3 g of TMAOH (25 wt %) is mixed with 115 g of water, towhich 3.79 g of aluminum isopropoxide is added and the hydrolysis iscarried out under stirring. To the resulting transparent gel, a solutionof 0.21 g of NaCl in 10 g of distilled water was added. Finally, 16.7 gof TEOS as silicon source is added and well stirred until beinghydrolyzed.

The composition of the gel thus obtained is as follows:

0.35 Al₂O₃: 1.5 TMA₂O: 0.1 Na₂O: 3 SiO₂: 300 H₂O.

The subsequent procedure of producing a zeolite foam is similar to thatof Example 1 and carried out at 50˜250° C.

Example 9 Preparation of a Mesoporous Silica foam Using a PolyurethaneSponge as a Template

A gel for the synthesis of mesoporous silica of MCM series is preparedas follows:

9.46 g of TMAOH is added to 104 g of distilled water, in which 19.66 gof cetyltrimethylammonium bromide (CTMAB) as a template is added anddissolved. To the resulting transparent solution, 21.2 g of TEOS isadded and well stirred until being hydrolyzed.

The composition of the gel thus obtained is as follows:

0.13 TMA₂O: 0.54 CTMAB: 1 SiO₂: 60 H₂O.

The subsequent procedure of producing a mesoporous silica foam issimilar to that of Example 1 and carried out at 50˜250° C.

Example 10 Preparation of a ZSM-5 Film Using a Polyurethane Film as aTemplate

The preparation of ZSM-5 film is similar to that of ZSM-5 foam describedin Example 2.

A polyurethane film alone without any support or a polyurethane filmattached on a support such as a glass, quartz, silicon wafer, porousalumina, porous stainless steel or the like is dipped in a gel for thesynthesis of ZSM-5.

The subsequent procedure similar to that of Example 1 is carried out toprepare a ZSM-5 film alone or on a support.

Example 10 Preparation of a Multi-layered ZSM-5 Film using aPolyurethane Film as a Template

Polyurethane resin and polycarbonate resin are coated by turns in amultiple layer on a support such as a glass, which is then dipped in agel for the synthesis of ZSM-5 as prepared in Example 1. The subsequentprocedure similar to that of Example 1 is carried out to prepare amulti-layered ZSM-5 film.

The above procedure can be applied to other various zeolite and zeotypematerial.

Example 11 Preparation of a ZSM-5 Film or Fibrous Material using Nylon,an Aromatic or Aliphatic Polyimide, Polyamideimide or Urea Resin

A film, membrane and fiber comprising various zeolite or zeotypematerial are prepared as in Example 1, except that polyurethane resin isreplaced with nylon, aromatic or aliphatic polyimide resin, polyimideresin or urea resin having a form of film, sponge, fiber or textile.

Thus obtained products have the same or similar shape of the film,sponge, fiber or textile used as a template.

This example shows that it is possible to produce various shapedarticles comprising zeolite or zeotype material depending on the shapeof templates used.

Example 12 SEM (Scanning Electronic Microscope) Analysis

A platinum/palladium coating with a thickness of about 15 mm is placedon a zeolite foam prepared according to the above described Examples,from which SEM photos are obtained by using a SEM (Hitachi S-4300).

Example 13 XRD (X-Ray Diffraction) Analysis

X-ray powder diffraction patterns are obtained from the zeolite foamsprepared according to the above described Examples by using CuKα X-rayto determine the degree of crystallization of the zeolite foams.

Industrial Applicability

According to the present invention, by using a polymeric templatecapable of releasing an amine which has a sponge or macroporousstructure and which has a form of 3-dimension mass, film, thread orwoven fabrics, it is possible to easily obtain a foam comprising zeoliteor zeotype material which has the outer shape and size and the innersponge or macroporous structure which are the same or similar to thoseof said polymeric template used.

Since the macroporous foam prepared according to the present inventionpossess macropores which are spatially communicated with each other andare huge enough for molecules to freely enter and leave, there is littleor greatly reduced pressure depression phenomenon when they are appliedto various fields.

What is claimed is:
 1. A method of the preparation of a foam comprisinga zeolite or zeotype material, which comprises dipping a polymerictemplate capable of releasing an amine in an alkaline or acidiccondition, into a gel or sol containing a precursor of the zeolite orzeotype material, and aging the resultant at a suitable temperature fora period such that all or almost all of the polymeric template can bereplaced with the zeolite or zeotype materials.
 2. The method accordingto claim 1, wherein said polymeric template capable of releasing anamine has a sponge or macroporous structure.
 3. The method according toclaim 1, wherein said polymeric template capable of releasing an aminehas a form of (i) a 3-dimensional mass, (ii) a film which may besupported by a support, (iii) a thread or (iv) a woven fabrics.
 4. Themethod according to claim 1, wherein said polymeric template capable ofreleasing an amine is selected from the group consisting of: (i) apolyurethane-typed polymer prepared by use of a polyol having two ormore alcohol groups and an isocyanate; (ii) a polyamide-typed polymer;(iii) an aromatic or aliphatic polyimide prepared by condensing adianhydride and a diamine; (iv) a polyamideimide-typed polymer; and (v)an epoxy resin-typed polymer in which an amine or its derivativeconstitutes the skeleton of the polymer.